The Basic Needs of Living Things

The Basic Needs Of Living
There are many things around us. Some of them are non-living things like table , chair, book, etc. Some are living things like animals and plants. Living things can grow, eat, reproduce, move, etc. Non-living things cannot grow, eat, reproduce or move by themselves. Living things need food, water, air and light for their survival.

Food

Living things need food to live and grow. Food makes them strong and healthy. It gives them energy. Some of the living things like plants can make their own food. They get energy from the sunlight. They use light energy to convert carbon dioxide and water into food.

Some living things cannot make their own food. They depend on plants and other animals for their food. Humans and animals are the examples of such living things (Figure 2.1).

Water

Water is very important for life. All plants and animals need water for survival (Figure 2.2).

Humans not only drink water but also use it in their daily life for cooking, washing, cleaning, etc. Plants also cannot make food without water

Air

Air is needed by all living things on the Earth. Humans have lungs in their body which help them breathe. Lungs take oxygen present in air and send it to whole body. Plants also use carbon dioxide from air to make food.

 Light

Light is a source of energy. All organisms need it. Plants cannot make food without sunlight

The Basic Needs of Living Things

Physical Characteristics of Life

Movement

Movement is a characteristic of life. Nonliving things cannot move on their own

Different groups of animals make different types of movements. This difference is due to their body structure and place where they live. Fish swim, frogs and kangaroos hop, birds fly, humans walk, etc

Plants as a whole remain fixed and do not change their position. However, most of their parts grow which can be considered as a sort of movement

Growth
Growth is one of the important characteristics present in living things and absent in non-living things. We have not seen a book, a chair or a pen increasing in size. The size of living things like humans, animals and plants continuously grows and gets bigger.
 

Reproduction

Reproduction is another characteristic which is present in the living things but absent in non-living things. Reproduction means producing their young ones. Dog produces puppies (Figure 2.4),

cat produces kittens (Figure 2.5). Rose plant produces baby rose plants.

Similarities and Differences Among Members of One Kind of Organisms

We have studied in class III that one kind of organisms resemble each other. For example, all humans are alike. They all have two eyes, two ears, hair, etc. But in the same kind of organisms, some differences also exist. We are not exactly like our parents. Some of the differences may be in eye colour, hair colour, height, skin colour, etc.

The Basic Needs of Living Things

Life Cycle

Life cycle means different stages which a living thing goes through during its life. Life Cycle of Plants A plant passes through various stages during its life time.

• The life cycle of a plant begins with the seed.

• In the next stage, a small root appears and begins to grow downward. Soon a shoot arises from the seed and grows upward.

 • This shoot grows and changes into a seedling. A seedling is a small plant with a few leaves.

 • The seedling develops into a young plant. The young plant grows into an adult plant and produces fruit. The seeds are produced in the fruit (Figure 2.6)